The present invention relates to control systems for gas turbine-generators and more particularly to a control system for providing improved frequency regulation under varying load conditions.
One of the primary advantages of utilizing gas turbine-generators in steam turbine and gas turbine power plants is the ability of the gas turbine to rapidly respond to changes in load conditions so as to maintain power system frequency substantially constant. To effect a desired percentage of frequency regulation, for example, 4 percent, the turbine control system must vary the fuel flow to the turbine in accordance with a preselected or programmed manner as a function of changes in system frequency. Unfortunately, in certain situations involving large changes in system frequency, the preprogrammed rate of loading or unloading a gas turbine provides an undesirably long period of time before system frequency is reestablished within the desired regulation limits.
Accordingly, it is an object of the present invention to provide an improved control circuit which responds more quickly to frequency deviations above a preselected deviation.
Another object of the invention is to provide dual regulation of power system frequency depending upon the extent of deviation from the desired system frequency.